26 CALIFORNIA ACADEMY OF SCIENCES. 



while the three anterior pepto-ncj)hri(lio-pores are in front of the fourth seta^ (fig 2). 

 Clitelhini is conspieious, occupying somites xiv to xvii, encroaching slightly on xiii 

 (fig. 2 and 15). ' 



In viewing the caudal end of tlie live worm a number of irregular white spots 

 are seen in mature sj^ecimens. These are rows of mature ova which agglomerate there 

 sometimes in large quantities. How they finally find their way through the oviduct 

 is not readily explained. 



SetiL' (figH. 2 and 4). As usual the setas begin in somite ii. All except 

 those in the penial sacs, are sigmoid and arranged in couples of two, eight in each 

 somite. The ventral setoe are about ^ closer than the lateral ones. Thus if we con- 

 sider the distance between the inner and outer coujiles to be 50, that between the 

 sette of the outer couple is 30, that between the setiie of the inner couple 22, that be- 

 tween the inner couples 40. This being the distance in somite xxvii, where it may 

 be said to be normal. In the region of the clitelhini, and posterior to it, the inner 

 setfe are unequally distant in the respective somites. Thus we may consider the inner 

 setfe 1 and 2, to have the normal distance from each other in somites xii to xxvii. 

 From these two somites the seta^ in the inner couples converge toward somite 

 xviii in which the setje are about ^ as tar apart as in xii and xxviii. In xvii the setse 

 of the inner couples are wanting. 



The innermost or row No. 1, forms a continuous line from one end of the body 

 to the otlier, while the row No. 2, forms an angle with somites xvii and xviii at the 

 apex. The setae in rows o and 4 are parallel and normal. The seta 1 in xviii is pre- 

 sent (pi. xii, fig. 4). 



This arrangement of the setfe appears very constant, and is charactei'istic of 

 the species, the details I)eing somewhat different in the other species of the genus, 

 while the general characteristics are the same. 'J'he normal setsB (fig. 16) of the 

 clitellum are not smaller than those of other parts of the body. The penial setae are, 

 however, very much the largest. 



Penial neife (fig. 17). The two pairs of sacs containing the penial seta^ are situated 

 in front of the spermiducal pore in somite xvii. They open immediately in front of 

 that pore, in a slit, at either end of which is situated a pore, each pore being tlie 

 outlet for the respective fork of the penial sac. The two sacs are connected at the 

 upper margin as usual l)y arciform muscles. Each sac contains not less than two, and 

 sometimes three or four setas straight or slightly curved, but not sigmoid. The seta' 

 vary considerably as regards shape, but resemble each other in not being sculptured, 

 and are only marked by rings. The penial sac reaches to the upper ]mrt of the mus- 

 cular part of the prostate. 



INTERIOR CHARACTERS. 



The Septn begin between somites iv and v. Those between vii and viii, and 

 following as far back as somite xiv, are slightly thickened, all, however, being of the 

 a me general thickness. 



The bodij irall contains the usual layers. The hypodermis is .slightly thinner 



